Most currently developed electronic products are miniaturized while they have powerful functions and constantly increased working frequency and operating speed. The higher the working frequency is, the more heat is produced during the operation of the electronic products. The electronic products tend to become unstable when they operate under a high-temperature state. Therefore, it has become an important issue to effectively and quickly remove waste heat from the electronic products to reduce an internal temperature thereof. The use of a fan is one of many economical ways to effectively remove heat from the operating electronic products. When a motor of the fan is actuated to rotate blades of the fan, electric energy is converted into mechanical energy, which is transferred via the blades to cause flowing of a fluid and increasing a coefficient of convection in a limited space, so that flowing of fluid produced by changes in pressure and increase of speed is used to carry away extra heat produced by the electronic products during operation thereof and achieve the purpose of dissipating heat.
Generally, when an amount of fluid is driven by the rotating blades of the fan to flow through an outlet of the fan, the fluid only diffuses into outer areas surrounding the fan. Since the fan is not able to control the flow direction of the fluid, a relatively large dead-air zone is formed behind a hub of the fan to largely reduce the radiation effect that may be achieved by the fan. When the conventional fan is mounted at a location having poor air ventilation and high impedance to dissipate heat produced by electronic elements, the dead-air zone behind the hub of the fan actually largely reduces the radiation effect that may be achieved by the fan, resulting in damaged electronic elements due to high temperature produced during working of the electronic elements.
Taiwanese Invention Patent Application No. 090118816 entitled “Sectional Fan and a Fan Frame Thereof” discloses a sectional fan that includes a fan and a fan frame. The fan frame further includes a first frame and a first flow-guiding element provided in the first frame. The first flow-guiding element includes a plurality of radially extended stationary blades. When the fan is rotated, the stationary blades are adapted to enhance the volume and pressure of airflow produced by the fan.
With the above-mentioned sectional fan, it is possible to produce an increased amount of fluid flown through the fan, however, it is unable to control the direction in which the fluid flown out of the rotating fan, just as in most cases of the conventional fans. Thus, there is still a relatively large dead-air zone behind the hub of the sectional fan to adversely affect the effective radiating of heat produced by the electronic products.
It is therefore tried by the inventor to develop an outlet airflow direction control device to eliminate drawbacks existed in the conventional radiating fans.